Reenforced box and box blank and method and machine for making the same



Jan. 31, 1961 REENFORCED BOX AND BOX BLANK AND METHOD AND Original FiledJan. 15, 1957 2 Sheets-Sheet 1 l'ilzlz zllllllll INVENTORS CHESTER E.CLAFF CARL A MOELLER Mammy,

ATTO RNEYS Jan. 31, 1961 c. E. CLAFF ETAL REENFORCED BOX AND BOX BLANKAND METHOD AND MACHINE FOR MAKING THE SAME Original Filed Jan. 15, 19572 Sheets-Sheet 2 Fig.ll

IN VEN TORS w U E Cmw M E m R& T EO YA TM 5 mm R 1 M Y B REENFORCED BOXAND BOX BLANK AND METHOD AND MAQE FOR MAKING THE SAME Continuation ofapplication Ser. No. 634,248, Jan. 15, 1957. This application Nov. 24,1959, Ser. No.

5 Claims. (Cl. 229-50) The present invention relates to the manufactureof boxes or cartons from pasteboard or the like and more particularly toa reenforced box and the blank from which it is formed and to the methodand machine for producing the reenforced blank.

This application is a continuation of copending application Serial No.634,248, filed January 15, 1957, now abandoned.

Some types of boxes or cartons, such, for example, as boxes in whichshoes are customarily packed and stored on the shelves of a retailstore, are subjected to considerable strain in use. This is due to thepractice of drawing the box outward from a stack by inserting one ormore fingers downwardly within the box or upwardly under the cover andpulling against the front wall of the box or cover. Inasmuch as theboxes of this type are generally stored in high stacks, often the boxthat is desired is in the middle or near the bottom of the stacks. Sincethe only practical manner that the box may be removed is as describedabove, where there is any appreciable weight on the box being removed,pulling the box out causes a heavy stress on the corners of the box orcover. Often this causes the corners to tear, resulting in a box orcover that is unsightly or unusable. This is a matter of concern to suchpersons as retail shoe dealers whose inventory is often stored where thepublic may see the shoe boxes. However, more important perhaps is thenecessity to replace torn boxes with new ones to make it possible tostore the inventory properly.

The problem of reenforcing cardboard boxes, particularly shoe boxes, hasbeen recognized before, and there have been many attempts to solve it.One of the commonest procedures is to apply an additional layer or stripof kraft paper or similar strong paper in the region of or around theedge of the box blank. Though some increase in tear resistance isobtained, it is considerably less than might reasonably be expected, andnot as much as desired. It has also been proposed that a twisted cord orstring may be laid along or adjacent the edge of the blank under thecover paper so as to provide added strength. However, this too has beenonly partially successful, as it is found that the ends of the stringpull out due to lack of anchoring, so that only moderate increase inresistance to tearing is obtained.

In providing corner reenforcing for boxes and cartons, not only must theincrease in strength be substantial in order to justify the extraexpense of the materials and the added step of incorporating thereenforcing means, but also the reenforcing must not add appreciably tothe wall thickness nor affect the finished appearance. It wouldtherefore appear that very thin but strong material might advantageouslybe used for reenforcing, provided it could be readily applied andefiectively anchored. On this basis, nylon or other synthetic fibermight be expected to provide the tensile strength coupled with smallcross-section, so as to make possible effective reenforcement withoutobjectionable thickness.

Tests conducted with nylon and rayon fibers as the Patented Jan. 31,1961 reenforcement, however, failed to show the expected increase inresistance to tearing at the corners. The anchoring of the fibers provedto be particularly difficult, yet unless the fibers were effectivelyanchored so as not to slip past the cardboard, the fibers addedpractically nothing to the strength of the box.

The present invention is therefore concerned, as a principal object,with the utilization and efiective anchoring of fibers or strands ofstrong synthetic materials such as nylon, rayon or the like so thatmarked improvement in the resistance to tearing of the box edges andparticularly the corners may be obtained.

More specifically, it is an object of the invention to provide a noveland effective reenforcement which may readily be embodied in the boxblank during fabrication and which involves appreciably less thicknessthan usual reenforcing means, so as to make possible the more compactstacking of blanks for storage and shipment.

With these and other objects in view, the present invention comprises abox or a cover blank having reenforcing threads effectively secured tothe edges of the sides and ends adjacent the corners of the box or coverblank so as to provide strong reenforcement of the corners againsttearing. A machine for automatically producing box blanks so reenforcedis likewise a feature of the invention.

Another feature of the invention involves the method of making and theprovision of a machine for producing such reenforced blanks rapidly andeconomically, so that the advantages of the improved blanks and boxesmay be made available at little if any extra cost.

In the accompanying drawings illustrating the present invention,

. Fig. 1 is a top plan view of apparatus for assembling web andreenforcing material for use in subsequent manufacture of shoe cartonsand the like.

Fig. 2 is a view in side elevation of the appartus shown in Fig. 1.

Fig. 3 is a sectional detail taken on the line 33 of Fig. 1 and showingthe relative positions of the cardboard, reenforcement, and cover paperprior to the time when the cover paper is pressed against the cardboard.

Fig. 4 is a sectional detail taken on the line 44 of Fig. 1 showing theparts after passing between the pressure rolls.

Fig. 5 is a sectional detail taken on the line 5-5 of Fig. 1 showing theedge of the assembled web after the cover paper has been folded aroundthe free edge of the cardboard.

Fig. 6 is an oblique detail, partly in section, showing the cornerportion of a completed box cover illustrating the location of thereenforcement.

Fig. 7 is a side elevation, partly in section, of the apparatus forsupplying and treating the reenforcing means according to the presentinvention.

Fig. 8 is a detail view in partial section of the mechanism adjacent theassembly point of reenforcement and cardboard, showing the guide meansfor the reenforcing fibers.

Fig. 9 is a detail view, partly in section, of the guide means of thepresent invention.

Fig. 10 is a detail sectional view of an edge of a web creased formaking a cover blank having a doublethickness side Wall, prior tofolding, showing the position of the reenforcing thread.

Fig. 11 is a detail sectional view of the web of Fig. 10 after the sidewing extension has been folded over, showing the position of thereenforcing thread.

' Fig. 12 is an oblique view taken similarly to Fig. 6 showing thecorner portion of a completed cover having a double thickness side walland incorporating the reenforcing means according to Figs. and 11 of thepresent invention.

Figs. 13 and 14 are views illustrating the reenforcement disposed at thetop edge of a double side wall box.

Figs. l5, l6, and 17 are views illustrating the steps of placing thereenforcing fibers at the top edge of a box.

The machine illustrated in Figs. 1 and 2 of the drawings may be of thesame general configuration as that shown in US. Patent No. 2,712,342,issued July 5, 1955 to C. L. Claif, C. E. Clafi and C. A. Moeller. Inthat machine, composite webs of cardboard and cover paper are assembledfor use in blank making apparatus to which the web may be supplied aspart of a continuous process. In view of the complete illustration anddescription of such laminating machine in said prior patent, only somuch of said machine will be described herein as is necessary for anunderstanding of the features of the present invention. The web ofcardboard 22 is supplied from a roll 24, from which it is drawn by thepower driven feed rolls 26. From the feed rolls 26 the web of cardboardpasses through the edge guides 28 which guide and align the webpreparatory to the covering operation.

The web of covering paper 30 is supplied from a roll 32 located belowthe cardboard. As the web of cover paper 30 is drawn from its supplyroll it passes between a guide roll 34 and glue roll 36. The glue roll36 is in contact with a roll 38 which is partially immersed in a tank ortrough 4% containing a suitable liquid gluing agent such as vegetablestarch glue with a tapioca starch, a corn starch, or a potato starchbase. The glue-coated cover paper is then drawn up to pressure rolls 44where the cover paper and cardboard web are combined under pressure.

After the pressure rolls 44, the combined web passes through edgefolding devices or plows 46 by which the projecting margins of the coverpaper are folded over onto the other face of the cardboard. Finalassembling pressure for the web is provided by the second set ofpressure rolls 48.

The machine so far briefly described resembles that of Patent No.2,712,342. The mechanism for handling the reenforcing fibers and theirmode of incorporation in the composite web will now be described.

As has been indicated, the reenforcement is preferably of high strengthsynthetic fibers such as nylon or rayon. These may be in the form or" athread having a small amount of twist (of the order of two turns perfoot) but it has been found still more efi'ective to make use of abundle of substantially parallel fibers not twisted. Such a bundle ofzero-twist fibers will tend to flatten out when applied to the web so asto form a very thin strip only a few fibers thick, so as to add noappreciable bulk to the finished blank. By way of example, a fiberbundle may consist of approximately 960 fibers of the order of 2200denier.

The synthetic fibers such as nylon and rayon, if directly assembled intocontact with the freshly glued surface of the cover paper prior toassembly with the cardboard, exhibit but little adhesion. It hastherefore been found, as an essential feature of the invention, that thefibers must be pretreated prior to assembly in the web.

The treating and supplying of the thread to the web machine isillustrated schematically in Figs. 2 and 7. The bundle of fibers,conveniently termed a thread 54, is drawn from the supply cone 56. Thethread is passed over a pair of bars 58 and under an intermediatetensioning rod 60. To provide the proper pretreatment, the thread thenpasses under a guide 62 at the end of arm 64 so as to carry the threadbeneath the surface of the treating solution within tank 66. The arm 64is mounted on a shaft 68 and so may be rotated to bring the end with theguide above the surface of the tank. When it is necessary to re-threadthe machine the arm is rotated to lift the guide out of the solution andpermit easy threading.

After passing under the guide 62 the thread is drawn through means forremoving excess solution. This comprises a rubber block 72 supported bya frame 74, the block having a slit to receive the thread. The slit maybe adjusted by a pressure screw 76 so that it will act as a meteringdevice to control the amount of removal of adhesive from the thread.Also it provides enough tension so that the thread will be supplieduniformly to the assembly point. An advantage of the rubber block withslit for the fiber bundle is that it permits knots in the thread to passthrough.

The treated thread then passes over a guide roll or rod 78 and into theadjustable thread guide 80. The thread guide 80 is supported on abracket 82 and is adjustably mounted laterally of the direction of webfeed. Since it is essential to strengthen the top edge of the cardboardto obtain the maximum amount of reenforcement, it is important that thethread guide 80 be capable of accurate adjustment so that the threadwill be brought into contact with the cardboard at the proper position.Thumb nut 84 and lock screws 86 are provided for positioning andsecuring the guide. The guide is shaped with a tapered tip so that itextends well into the bite between the cardboard and the cover paper. Asa result, the fibers are effectively guided into precise alignment withthe Web edge and are thereupon flattened out along the outer edge of thecardboard between the glue-coated cover paper and the cardboard as theassembly passes between the pressure rolls.

As discussed above, it is essential that the synthetic thread besuitably treated prior to the time it is fed into contact with thecardboard and the glue-coated cover paper. This is necessary since thethin film of glue or adhesive on the cover paper is ineffective to bondthe fibers. If, however, the multiple fiber synthetic thread, such asnylon or rayon, is first impregnated with a suitable adhesive, itbecomes possible to provide a reenforcing means that is vastly superiorto previously known materials and techniques.

In order to provide a satisfactory adhesive it is necessary to providean agent that has an afiinity for all the materials that are beinganchored together: cardboard, cover paper, vegetable glue or othercommonly used bonding material, and the synthetic fibers. A suitableadhesive agent that has been found to have the necessary properties is awater emulsion of polyvinyl acetate resin. The thread is preferablypassed through the tank 66 in a loose state so that all the fibers willhave an opportunity to become impregnated with the adhesive. As a meansof insuring complete wetting of all the fibers a small amount of awetting agent, such as the salts of homologous series of substitutedaromatic sulfonic acids (for example, Santomerse manufactured byMonsanto Chemical Co.), is added to the adhesive agent in the tank 66.The wetting agent and the adhesive agent cooperate to impregnatethoroughly the individual fibers, thereby making possible an efiectiveand permanent bond between the thread, cardboard, cover paper, and glueused with the cover paper. Passage of the fiber bundle through the slitin the rubber block 72 serves to meter the amount of adhesive on thethread and aids in insuring the impregnation of all the fibers. In thismanner the thread comes to the assembly point at pressure rolls 44thoroughly impregnated with an adhesive that will bond to all of theelements that are anchored together.

As the cardboard 22, adhesive impregnated thread 54 and the glue-coatedcover paper 30 approach the pressure rolls 44 the position of the threeelements is as shown in Fig. 3, Fig. 4 shows their relative positionafter they have been pressed together by the rolls 44. After passingthrough the rolls the web assembly passes through plows 46 shaped toturn over the projecting margins of the cover paper around the edges ofthe cardboard and onto the top marginal surface of the cardboard. Thenthe combination passes under the second set of pressure rolls 48 whichpress the elements forcibly together to complete the web assembly, themarginal portion of which is shown in Fig. 5.

After the elements have been secured together the web is advanced to theconventional creasing, slitting and severing mechanisms for producingbox or cover blanks of conventional form. A box cover made from such areenforced blank is shown in Fig. 6. Side wings 88 which are turned upto form the sides of the cover, with the side wing extensions turnedinwardly to form corner laps 90 joining the upstanding end wings 92 andinturned end wing extensions. As may be seen in Fig. 6, the thread orfiber bundle 54, flattened into a strip, reenforces the areas where thegreatest stress is placed on the cover when it is in use. Since all ofthe individual fibers are impregnated with adhesive and firmly anchoredto the cardboard and cover paper, it is necessary to break the threadbefore the corner will give way. Thus all of the tensile strength of thethread is employed as a reenforcing means to prevent the box or coverfrom tearing or breaking.

A further advantage that is gained from the use of synthetic multiplefibers flattened out over the surface at the edge of the cover or boxblank is that such reenforcement adds very little thickness to theblanks. This is of great importance since a larger number of box blanksmay be stored in a given place, and smaller sized shipping cases may beused at a saving in cost. Also, the blanks provide a better printingsurface, resulting in less wear on the rubber blankets of offsetprinting presses and improved printing quality, and avoids theblistering of the cover paper over the cord or thread, such as sometimesencountered when conventional reenforcing materials are employed.

The reenforcement of the invention may likewise be employed inconjunction with boxes of the double side wall type. The apparatus foraccomplishing this may be the same as heretofore described, withsuitable adjustment of the guide so that the thread or fiber bundle 102is laid on the cardboard web adjacent the outer longitudinal fold line104, as illustrated in Fig. 10. In order that the reenforcement may liewithin the folded side wall, as shown in Fig. 11, the thread is laid onthe side of the cardboard opposite to the cover paper. The dispositionof the flattened fiber bundle within the side wall 106 and around thecorner lap 108 into the end 110 of the box cover is apparent in Fig. 12.

As an alternative to the placement shown in Figs. 10, 11 and 12 in thedouble side wall embodiment, the reenforcing fibers may initially beguided into the inside of the fold line 112 for the double side wall,according to Fig. 13. This places the fiber bundle between the cardboardweb and the cover paper, as in the first described embodiment.

The position of the reenforcement when the folding of the side walls iscompleted is shown in Fig. 14, wherein the thread 114 is at the top edgeof the wall, directly beneath the cover paper. While such position islogically the most effective location to prevent the inception oftearing at the corners, it has heretofore proved diflicult to obtain,due to inability to anchor the thread positively in the desiredlocation.

This same highly advantageous location of the reenforcing fibers islikewise possible in boxes having a single side wall thickness. As shownin Figs. 15, 16 and 17, just before assembly of the cardboard body stock116 and cover paper 118 occurs, the bundle of reenforcing fibers 120 maybe laid accurately on the cover paper so as to lie immediately adjacentthe edge of the cardboard. Upon folding the margin of cover paper aroundthe cardboard, the fibers are compacted into a firm bundle supported onthe edge of the cardboard. With the setting of the adhesive, the fibersbecome secured to the cardboard so that the assembly of cover paper,longitudinal fibers and cardboard provide great resistance to theinception of tearing, in the exact region where reenforcement is mosteffective.

With the pre-treatment of the fiber bundle prior to incorporation in thecardboard and cover paper assembly,

coupled with the use of synthetic fibers of great strength, it is nowpossible to anchor the fibers not only against longitudinal slippage butalso against lateral separation. As a consequence, the location ofreenforcing fibers even at the top edge of the cardboard walls becomespractical and effective.

It is to be noted that the invention contemplates the use of a bundle ofa multiplicity of synthetic fibers, either having a slight twist (up toabout two turns per foot) but preferably having zero-twist, It has beenfound that the parallel fibers of the zero-twist bundle permit betterpenetration of the pre-treating adhesive and consequently a moreeffective final bond in the cardboard and cover paper assembly.Furthermore, the untwisted bundle permits flattening into a thin band toa greater degree than even a slightly twisted bundle. As a consequence,the zero-twist bundle will generally be found to provide even betteranchoring and greater reenforcing value than the twisted bundle, thoughthe latter still permits a substantial improvement over priorreenforcing procedures and is therefore comprehended within theinvention.

Thus it may be seen that the present invention represents a substantialimprovement over the prior methods of reenforcing box and cover blanks.While the present invention has been illustrated and described invarious advantageous embodiments, it will be appreciated by thoseskilled in the art that the method and apparatus involving preliminarytreatment of synthetic fibers is applicable to other modes andarrangements of reenforcement for boxes and box blanks within the scopeof the appended claims.

Having thus described the invention what we claim is:

1. A box blank comprising a web of cardboard having a longitudinallyextending side wall portion and an intejgral corner lap at one end ofthe side wall portion, the web having a marginal edge extending alongthe side wall portion and corner lap, a layer of cover paper folded oversaid marginal edge, edge and corner reenforcing means including amultiplicity of fine synthetic fibers extending along said web inoverlying relation thereto and disposed closely adjacent to the marginaledge surface of the blank and between the web and cover paper, avegetable starch base first adhesive disposed on the surface of thecover paper next adjacent the side wall portion and corner lap andbonding the cover paper to the web, and a second adhesive of a typeother than a vegetable starch base adhesive bonding the fibers to saidmarginal edge surface and bonding the fibers to the first adhesive onthe portion of the cover paper overlying the fibers, said secondadhesive further anchoring said fibers against lateral separation, saidsecond adhesive being compatible with said first adhesive and saidfibers and said web.

2. A box blank comprising a web of cardboard having a longitudinallyextending side wall portion and an integral corner lap at one end of theside wall portion, the web having a marginal edge extending along theside wall portion and corner lap, a layer of cover paper folded oversaid marginal edge, edge and corner reenforcing means including a bundleof fine synthetic fibers having a twist of from zero up to approximatelytwo turns per foot of length of the bundle, the bundle of fibers beingdisposed along and in overlying relation to the marginal edge surface ofthe blank and beneath the cover paper, a vegetable starch base firstadhesive disposed on the surface of the cover paper next adjacent theside wall portion and corner lap and bonding the cover paper to the web,and a second adhesive of a type other than a vegetable starch baseadhesive bonding the bundle to said marginal edge surface and bondingthe bundle to the first adhesive on the portion of the cover paperoverlying the bundle, said second adhesive further anchoring said fibersagainst lateral separation, the bundle conforming to and filling theregion intermediate the cover paper and said marginal edge of the web.

3. In a pasteboard box and the like of a type including a side wall, anintegral corner lap at one end of the side wall and extendingangularlyof the side wall, an end wall disposed at least partially inoverlapping relation to said corner lap, the side wall and the cornerlap having a contiguous outer edge surface, and a layer of cover paperfolded over said outer edge surface and extending along and overlyingthe side wall and corner la-p surfaces bordering said outer edge surfacealong at least a portion of said side Wall and a contiguous portion ofsaid corner lap; the improvement of the combination of a multiplicity ofsynthetic fibers disposed closely adjacent said outer edge surface andextending along the side wall and corner lap and disposed betweenthecover paper and the side wall and corner lap, a vegetable starch basefirst adhesive covering the surface of the cover paper next adjacent theside wall and corner lap and said fibers and bonding the cover paper tothe side wall and corner lap, and a. second adhesive of a type otherthan a vegetabale starch base adhesive covering said multiplicity offibers and bonding said multiplicity of fibers to the side Wall andcorner lap and to the first adhesive on the overlying cover paper, saidsecond adhesive being compatible with said fibers and said firstadhesive and the side wall and corner lap material.

4. Ina pasteboard box and the like of a type including. a side wall, anintegral corner lap at one end of the side wall and extending angularlyof the side wall, an end wall disposed at least partially in overlappingrelation to said corner lap, the side wall and the corner lap having acontiguous outer edge surface, and a layer of cover paper folded oversaid outer edge surface and extending along and overlying the side walland corner lap surfaces bordering said outer edge surface along at leasta portion of said side wall and a contiguous portion of said corner lap;the improvement of the combination of a multiplicity of synthetic fibersextending along and in overlying relation to said outer edge surface anddisposed between the cover paper and the side Wall and corner lap, avegetable starch base first adhesive covering the surface of the coverpaper next adjacent the side wall and corner, lap and said fibers andbonding the cover paper to the side wall and corner lap, and a secondadhesive of a type other than a vegetable starch base adhesive bondingthe fibers to said outer edge surface of the side wall and corner lapand to the first adhesive on the. overlying cover'paper, said secondadhesive being compatible with said fibers and said first adhesive andthe side wall and corner lap material and anchoring the fibers againstlateral separation.

5. In a pasteboard box and the like of a type including a side Wall, anintegral corner lap at. one end of the side wall and extending angularlyof the side wall, an end wall disposed at least partially in overlappingrelation to said corner lap, the side wall and the corner lap having acontiguous outer edge surface, and a layer of cover paper folded oversaid outer edge surface and extending along and overlying the side walland corner lap surfaces bordering said outer edge surface along at leasta portion of said side wall and a contiguous portion of said corner lap;the improvement of the combination of a bundle of fine synthetic fibersoverlying said outer edge surface and extending along the side wall andcorner lap and disposed between the cover paper and said outer edgesurface, the bundle of fibers having a twist of from zero toapproximately two turns per foot of length of the bundle, a vegetablestarch base first adhesive covering the surface of the cover paper nextadjacent the side wall andcorner lap and said bundle and bonding thecover paper to the side wall and corner lap, and a second adhesive of atype other than a vegetable starch base adhesive covering said bundleand bonding the bundle to said outer edge surface and to the firstadhesive on the overlying cover paper, said second adhesive beingcompatible with the fibers of said bundle and said first adhesive andthe side wall and corner lap material and anchoring the fibers of saidbundle against lateral. separation, said bundle of fibers conforming toand filling the region between the cover paper and said outer edgesurface.

References Cited in the file of this patent UNITED STATES PATENTS900,904 Wyrnan Oct. 13, 1908 905,806 Fraser Dec. 1, 1908 1,762,704 SmithJune 10, 1930 2,646,914 Clalf July 28, 1953 2,732,121 McGovern Jan. 24,1956

